Numerical simulation of inorganic Cs2AgBiBr6 as a lead-free perovskite using device simulation SCAPS-1D

Double perovskite, Cs2AgBiBr6, is introduced as a lead-free perovskite solar cell. Device modeling of Cs2AgBiBr6 (DP) was accomplished to obtain the optimum parameters using the Solar Cell Capacitance Simulator (SCAPS). Two devices with two different hole transport layers (HTLs) were investigated, including P3HT and Cu2O. For both devices with different HTLs, an optimal thicknesses of 1200 nm and defect densities of 1.0x 10(14) cm(-3) for DP layer were attained. For both HTLs, conduction band offset, CBO, is - 0.21 eV and valence band offset, VBO, is + 0.16 eV. For shallow acceptor doping concentration of P3HT and Cu2O, the values of 5.0 x 10(19) and 5.0 x 10(17) cm(-3) were obtained, respectively. As far as the shallow donor density of electron transport layers (ETLs) is concerned, for both cases, the optimum value of 5.0x 10(19) cm(-3) were achieved. For capture cross section, sigma(n,p), in absorber layer for both HTLs, the optimal value at sigma(n,p) of 10(-20) cm(2) for N-t,N-DP(defect density of DP) is10(16) cm(-3), at sigma(n,p) of 10(-19) cm(2) for N-t,N-DP is10(15) cm(-3), at sigma(n,p) of 10(-18) cm(2) for N-t,N-DP is 10(14) cm(-3), at sigma(n,p) of 10(-17) cm(2) for N-t,N-DP is 10(13) cm(-3), and at sigma(n,p) of 10(-16) cm(2) for N-t,N-DP is 10(12) cm(-3). For P3HT device, the interface defect density of P3HT/Cs2AgBiBr6 is occurred at 1.0 x 10(14) cm(-2), and for Cs2AgBiBr6/SnO2 is happened at 1.0 x -10(9) cm(-2). For Cu2O device, the interface defect density of Cu2O/Cs2AgBiBr6 is befallen at 1.0 x 10(13) cm(-2), and for Cs2AgBiBr6/SnO2 is happened at 1.0 x 10(10) cm(-2). As for radiative recombination, for P3HT device, the optimal value is happened at 2.3 x 10(-13) cm(3)/s, however, for Cu2O device is occurred at 2.3 x 10(-12) cm(3)/s. Finally, for P3HT device, a maximum power conversion efficiency, PCE, of 11.69% (open-circuit voltage, -Voc, of 2.02 V, short-circuit current density, J(sc), of 6.39 mA/cm(2), and fill-factor, FF, of 0.90 (90%)) were achieved, and for Cu2O device, a PCE of 11.32% (V-oc of 1.97 V, J(sc) of 6.39 mA/ cm(2), and FF of 0.895 (89.5%)) were attained. This is the highest efficiency for Cs2AgBiBr6 double perovskite solar cell which was achieved till now. Finally, our results are providing towards fabricating a lead-free and inorganic solar cell.

Automated summary

In this study, the lead-free double perovskite Cs2AgBiBr6 was introduced as a new material for solar cells, with device modeling conducted to optimize parameters. Different hole transport layers (HTLs) were investigated for the devices, and optimal thicknesses and defect densities were obtained for the Cs2AgBiBr6 layer in both cases. Results also detailed the performance of the cells with various HTLs.